JP4798686B2 - Ethylene / vinyl acetate copolymer resin composition for calendar molding - Google Patents

Description

  The present invention relates to an ethylene / vinyl acetate copolymer resin composition for calender molding. More specifically, the present invention relates to an ethylene / vinyl acetate copolymer resin composition for producing a film or sheet that is flexible, heat shrink resistant, has a good surface gloss, and has no surface irregularity by calendar molding. is there.

Ethylene / vinyl acetate copolymer (hereinafter referred to as EVA) is flexible, has good transparency, is suitable for high-frequency welders, and is inexpensive. Films and sheets are used for food packaging and agriculture. Used for medical, industrial materials, stationery, etc.
Conventionally, these products have been manufactured from soft vinyl chloride resin. Generally, a soft vinyl chloride resin is produced by blending a plasticizer with a vinyl chloride resin. A vinyl chloride resin blended with a plasticizer has good moldability when producing a film or sheet, and the film or sheet also has good secondary processability such as vacuum forming or printing. Further, chlorine corresponding to about 60% by weight of the raw material is made through the use of sodium chloride, and is a resin that contributes greatly to the resource problem because of its low dependence on petroleum among resin materials. It is also price competitive.
However, in recent years, the amount of soft vinyl chloride resin used has decreased due to various problems. First, regarding plasticizers, there are problems related to environmental hormones. In addition, migration of the plasticizer from the product may be a problem. Moreover, there is a problem related to heavy metals with respect to the stabilizer to be blended when molding a soft vinyl chloride resin. Further, there is a problem related to dioxin gas generated when a soft vinyl chloride resin is burned. Therefore, soft vinyl chloride resin is suitable as a resin material for films and sheets in terms of economy, moldability, and performance, but a product to replace it in relation to the above problems. Development is underway.
Here, as a substitute material for the soft vinyl chloride resin, a polyolefin resin is representatively exemplified from the viewpoint of similarity in performance and cost. Among these, considering the softness, a low crystalline ethylene copolymer obtained by copolymerizing various monomers with ethylene is preferable.
As for the ethylene-based copolymer, those having different performance are produced depending on the kind of monomer copolymerized with ethylene and the production method. Specifically, non-polar comonomers such as propylene, butene, hexene and octene are copolymerized with ethylene, or polar comonomers such as vinyl acetate, methyl methacrylate, methyl acrylate, ethyl An acrylate may be copolymerized with ethylene. In addition, the molecular structure of the ethylene-based copolymer varies depending on the resin production method, and the difference in the molecular structure affects the moldability.
Among ethylene-based copolymers, EVA is a copolymer of nonpolar comonomer, because vinyl acetate comonomer has polarity, and has high-frequency welder characteristics that are characteristic of films and sheets made of soft vinyl chloride resin. It has characteristics that are not found. In addition, the cost is lower than that obtained by copolymerizing other comonomer having polarity. Further, due to the influence of the resin production method, the resin has a good melt processability, and in particular, a resin having a high melt tension suitable for calender molding frequently used when molding a soft vinyl chloride resin. As described above, EVA has advantages over other similar polyolefin resins in various aspects.
As described above, EVA is suitable as an alternative material for soft vinyl chloride resin in various aspects, but the film and sheet made of EVA are resistant to heat shrinkage compared to those made of soft vinyl chloride resin. There is a disadvantage that it is inferior. In contrast to vinyl chloride resin, which is softened by adding a plasticizer, in the case of polyolefin resin, especially ethylene copolymer, other monomers are copolymerized with the main monomer to become the main component. It is softened by reducing the number of hard crystal parts composed of monomer chains. However, the crystal part has better heat resistance than the other non-crystal parts, and the reduction of the crystal part reduces the heat resistance of the entire material. Further, when softened by copolymerization, the amount of crystal portion is reduced, and at the same time, the melting point is lowered, and the heat resistance is also lowered from this aspect.
Here, a film or sheet made of EVA is manufactured by extrusion molding, inflation molding, or calendar molding. Among these, calender molding is capable of high-speed production and a film having a good thickness accuracy is obtained. In these respects, the calender molding is superior to the extrusion molding and the inflation molding. Calender molding is a molding method in which a sheet or film having a desired thickness is produced by rolling a molten resin with a heated metal roll (calender roll), and there is no trouble occurring near the die in extrusion molding. Calendar molding is a processing method suitable for soft vinyl chloride resin, and many films and sheets made of soft vinyl chloride resin are manufactured by calendar molding.
On the other hand, for EVA, since a molten resin adheres to a high-temperature metal, it is necessary to select a suitable lubricant in order to produce a film or sheet by calendar molding. Examples of suitable lubricants for EVA are exemplified in Patent Document 1 and the like.
For EVA, when a film or sheet is produced by calendering, there are problems that surface gloss cannot be obtained and pattern unevenness occurs on the surface. Specifically, the entire surface becomes rough, and the transparency of the film or sheet cannot be obtained, and the flow of the melt in the molten resin pool (referred to as a bank in the field) between the calender rolls is not good. The unevenness of the partial pattern accompanying the mark (referred to as a flow mark in the art) that is uniform and reflects the non-uniformity of the flow occurs on the surface of the film or sheet.
Therefore, EVA is suitable as a substitute material for soft vinyl chloride resin from the viewpoint of performance and cost, but with the flexibility that is the characteristic of the material, heat shrink resistance is imparted, and calendar molding is performed. In addition, it is difficult to produce films and sheets with good thickness accuracy at high speed, and to obtain films and sheets with good surface gloss, transparency, and no pattern irregularities due to flow marks. there were.
JP 2001-31822 A

As a result of intensive studies to solve the above-mentioned problems, the present inventors blended a specific amount of a specific polyolefin-based resin with a specific ethylene / vinyl acetate copolymer, and a specific amount of lubricant and It has been found that a composition containing an antioxidant can solve the above-mentioned problems, and has completed the present invention.
The object of the present invention is an ethylene / vinyl acetate copolymer resin for producing a film or sheet that is flexible, heat shrink resistant, has a good surface gloss, and has no pattern irregularity by calender molding. It relates to a composition.

The ethylene / vinyl acetate copolymer resin composition of the present invention that achieves such an object has a value (Mw / Mn) of 2.0 to 4.0 obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn). The ethylene-vinyl acetate copolymer has a vinyl acetate content in the range of 10 to 35% by weight, a melting point of 100 ° C. or higher, and the weight average molecular weight (Mw) is a number average. molecular weight (Mn) of a value obtained by dividing molecular weight distribution (Mw / Mn) a resin component consisting of 5-50% of one or more polyolefin resins excluding the ethylene-vinyl acetate copolymer I 2.0-4.0 der in 0.3 to 3.0 parts by weight of a lubricant selected from fatty acids having 21 or more carbon atoms, amide compounds, ethylene bisamide compounds, ester compounds and metal soaps with respect to 100 parts by weight, antioxidants 0.05 to 2.0 weight A composition to be blended (claim 1).
At this time, in consideration of making the surface of the obtained film or sheet a uniform glossy surface with no pattern unevenness in a wide range of processing conditions in calendar molding, the melt flow rate (MFR) of the ethylene / vinyl acetate copolymer is considered. ) Is preferably 1.3 to 10 g / 10 min (claim 2).

The composition of the present invention is applied to a conventionally known calender molding method, and has a thickness in a range of 50 to 500 μm, is flexible, has heat shrink resistance, has a good surface gloss, and has a pattern by a flow mark. An uneven film or sheet can be produced at high speed.
The obtained film or sheet can be widely used as a film or sheet for a tape substrate such as an adhesive tape, food packaging, agricultural, medical, industrial material, or stationery.

Hereinafter, preferred embodiments of the present invention will be described in detail.
EVA used for the composition in the present invention is limited to those having a value (Mw / Mn) in the range of 2.0 to 4.0, obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn). Here, when Mw / Mn is less than 2.0, the melt tension of the melt is reduced, and when the sheet-like melt is peeled off from the calender roll, sagging occurs due to its own weight, and the obtained film or sheet Unevenness in thickness occurs. Increasing the melt viscosity of the resin or lowering the temperature of the melt during processing can solve this problem, but the surface gloss of the film or sheet deteriorates, and if the processing temperature is increased to obtain the surface gloss, it will melt. The body sticks to the calendar roll and cannot be processed. Moreover, when Mw / Mn becomes smaller than 2.0, the non-Newtonian property of the shear viscosity of the melt increases. Therefore, the load applied to the rotating calendar roll becomes large, and it becomes difficult to produce a thin film by narrowing the interval between the calendar rolls, or to rotate the calendar roll at a high speed and to manufacture a film or a sheet at a high speed. . This problem can also be solved by raising the temperature of the melt during processing. However, since the melt tension of the melt is further reduced, drooping when peeling the melt from the calender roll becomes significant. Further, depending on the processing temperature, it adheres to the calendar roll and cannot be processed.
On the other hand, if Mw / Mn exceeds 4.0, the surface of the film or sheet obtained by calendering becomes rough and transparency cannot be obtained, and a molten resin pool between calender rolls (referred to as a bank in this field). )), The flow of the melt is not uniform, and pattern irregularities due to flow marks occur on the surface of the film or sheet.
Therefore, when producing a film or sheet by calender molding, it has a melt tension that can suppress drooping due to its own weight, provides a surface gloss, and the flow of the melt in the bank is uniform and flows to the surface of the film or sheet. EVA Mw / Mn is limited to a range of 2.0 to 4.0 in order to obtain a film or sheet made of EVA having no pattern unevenness due to the mark at high speed by calendar molding.

Here, regarding the melt flow rate of EVA used in the present invention (hereinafter referred to as MFR), considering that a film or sheet having a thickness of 50 to 500 μm is produced by a calendering method, EVA has an MFR of 190. It is preferable that the value measured under the load of 2160 g at 0 ° C. is 0.5 to 10 g / 10 min. When the MFR is less than 0.5 g / min, the processing condition width for obtaining the surface gloss of the film or sheet is narrowed. However, when the MFR exceeds 10 g / 10 min, the melt tension of the melt is increased. When the melt is peeled off from the calender roll, the processing condition width capable of suppressing sagging due to its own weight is narrowed.
In the present invention, several EVAs having different MFRs can be mixed for the purpose of improving the calendar moldability. However, also in that case, it is necessary that Mw / Mn of the composition obtained as a result of mixing is in the range of 2.0 to 4.0.

  In the present invention, the molecular weight of EVA to be used is not particularly limited. However, as described above, since there is a range of MFR suitable for EVA, a molecular weight in a range corresponding to the MFR is suitable.

In the present invention, it is necessary that the content of vinyl acetate in EVA is in the range of 10 to 35% by weight. When the vinyl acetate content of EVA is less than 10% by weight, the flexibility of EVA is inferior. When a polyolefin resin having a melting point of 100 ° C. or higher is blended to impart heat shrink resistance, the flexibility is insufficient. On the other hand, when the vinyl acetate content exceeds 35% by weight, adhesion of the melt to a high-temperature metal roll becomes significant, and it cannot be peeled off from the roll unless a large amount of lubricant is blended. However, when a large amount of lubricant is blended, the lubricant swells on the surface of the film or sheet obtained by calendering (referred to as bleed out in this field), and an adhesive or adhesive is applied to the surface of the film or sheet. Cause troubles when printing or printing.
Therefore, in order to produce a flexible film or sheet with EVA as a main component and having no lubricant bleed out on the surface, the content of vinyl acetate in EVA is in the range of 10 to 35% by weight. Limited.
In the present invention, several kinds of EVA having different vinyl acetate contents can be mixed for the purpose of improving mechanical properties. However, even in that case, it is necessary that the vinyl acetate content of the composition obtained as a result of mixing is in the range of 10 to 35% by weight on average, and Mw / Mn is 2.0 to 4.0. Must be in range.

On the other hand, in the present invention, it is necessary to blend 5 to 50% of one or more polyolefin resins having a melting point of 100 ° C. or higher with EVA. Here, the polyolefin-based resin is blended in order to impart heat shrink resistance to a film or sheet produced by calendar molding using the composition. In view of the object of the present invention to produce a film or sheet having a melting point of 100 ° C. or higher, which is hard, flexible, and having good heat shrinkage resistance, a polyolefin resin having a melting point of 100 ° C. or higher is 50. It is not preferable to exceed the weight percentage and become the main component. Although it is understood that a composition having a polyolefin resin having a melting point of 100 ° C. or higher as a main component has good heat shrink resistance, the present invention is characterized by a composition having EVA having a low melting point as a main component. However, good heat shrinkage resistance can be obtained even at a temperature equal to or higher than the temperature at which EVA melts. This is a phenomenon that is difficult to envisage when polyolefin resins having a melting point of 100 ° C. or higher are dispersed independently in a nearly spherical shape in an EVA matrix as a main component. When the phase structure of the film or sheet obtained by calender molding is observed with a scanning electron microscope, the polyolefin resin having a melting point of 100 ° C. or higher has a continuous structure even in a small amount, and particularly represented by calender molding. Thus, when the process of extending | stretching a melt enters when producing a film and a sheet | seat, the structure where the fiber structure which consists of polyolefin resin orientated in the extending | stretching direction at the fiber form is observed. Therefore, with regard to the composition, a polyolefin resin having a melting point of 100 ° C. or higher has a continuous fibrous structure in a calendered film or sheet even with a small amount of components, and this structure exhibits good heat shrink resistance. It is understood that
Here, when the blending amount of the polyolefin resin having a melting point of 100 ° C. or higher is 5% by weight, the blending amount is too small to obtain sufficient heat shrink resistance. On the other hand, when the blending amount of the polyolefin resin having a melting point of 100 ° C. or higher exceeds 50% by weight, the molded body becomes hard and the flexibility cannot satisfy the target. Accordingly, sufficient heat shrink resistance can be obtained, and when trying to satisfy flexibility, the polyolefin resin having a melting point of 100 ° C. or higher is limited to the range of 5 to 50 weight. .
Moreover, in this invention, melting | fusing point of polyolefin resin is limited to 100 degreeC or more. Even if the melting point of the polyolefin resin is lower than 100 ° C., the heat shrink resistance may be exhibited when the temperature at which the heat shrink resistance is required is lower than 100 ° C. However, regarding heat-resistant heat shrinkability that can be imparted by blending a polyolefin resin having a melting point lower than 100 ° C., the temperature range in which the effect can be expected is narrow, and applicable applications are limited. The polyolefin resin having a melting point lower than 100 ° C. can impart heat shrink resistance to EVA having a high vinyl acetate content. A polyolefin resin having a low melting point can be applied to EVA having a high vinyl acetate content. Since it mix | blends, the molded object which consists of those compositions has a sticky feeling, and is unpreferable practically. Therefore, in order to have a wide temperature range in which heat shrink resistance can be exhibited and the film or sheet obtained by calendering has no stickiness, the polyolefin resin blended with EVA should have a melting point of 100 ° C. or higher. Limited. On the other hand, the upper limit of the melting point of the polyolefin resin is not particularly limited. However, in view of the fact that the thermal stability of EVA is inferior to that of other polyolefin resins, a polyolefin having a high melting point that does not melt unless the temperature is considerably high. A resin based on EVA is not preferable for blending with EVA.
Here, the type of polyolefin resin having a melting point of 100 ° C. or higher is not particularly limited, and examples thereof include high-density polyethylene, low-density polyethylene produced by a high-pressure radical polymerization method, and a copolymer of ethylene and α-olefin. Linear low density polyethylene obtained by polymerization, and poly-α-olefin resins such as polypropylene and poly- (1-butene), and random copolymer resins obtained by copolymerizing a small amount of ethylene with propylene, and ethylene Examples thereof include an ethylene / vinyl acetate copolymer obtained by copolymerizing a small amount of vinyl acetate. Among these, the temperature range in which heat shrink resistance can be imparted is wide, and a molded body can be produced without molding at a high temperature exceeding 250 ° C. High-density polyethylene having a high melting point and a polypropylene resin having a melting point of 160 ° C. are preferable.

Moreover, the composition of this invention produces a film and a sheet | seat by calendar molding. For that purpose, it is necessary to peel the molten resin from the high temperature calender roll. In the case of a composition mainly composed of polar EVA, the resin component is used to peel the melt from the high temperature calender roll. It is necessary to blend 0.3 to 3.0 parts by weight of the lubricant with respect to 100 parts by weight.
Here, the type of lubricant, releasability from metals made of hot roll well, (referred to as plate-out in the art.) Excessive adhesion of lubricants to the metal roll and a lubricant to a film or sheet surface A lubricant with a low level of upwelling (referred to in the art as bleed out) is preferred. Suitable lubricants include fatty acids having 21 or more carbon atoms such as behenic acid and montanic acid, amide compounds such as stearic acid amide, oleic acid amide, and erucic acid amide, ethylene bis stearic acid amide, ethylene bis Metal soap such as oleic acid amide, ethylene bisamide compound such as ethylene biserucic acid amide, diester of montanic acid and ethylene glycol, ester compound such as polymer composite ester, zinc stearate, zinc behenate, magnesium behenate Etc.
Here, when the blending amount of the lubricant is less than 0.3 parts by weight, the peelability of the molten resin from the calender roll is insufficient, and when the blending amount is more than 3.0 parts by weight, When the lubricant is plated out on the calender roll and the appearance of the film or sheet is impaired, or the lubricant is bleed out on the surface of the obtained film or sheet, and printing or applying adhesive to the film or sheet Cause printing failure and adhesive application failure.
Therefore, in order to prevent the lubricant from being plated out on the calender roll during calendering and causing various problems due to stable peeling from the high temperature calender roll, blending of the lubricant with 100 parts by weight of the resin component The amount is limited to the range of 0.3 to 3.0 parts by weight.

Moreover, about the composition of this invention, in order to produce the film and sheet | seat by calendar molding, in order to prevent the oxidation of molten resin, it is 0.05-2.0 antioxidant with respect to 100 weight part of resin components. It is necessary to blend parts by weight. EVA is prone to oxidative degradation among polyolefin resins, and the calendar molding method is a molding method in which a high-temperature molten resin is often exposed to air, and therefore, an antioxidant is indispensable. .
Here, considering the antioxidant performance of EVA and preventing the plate-out to the calender roll and the bleed-out to the film or sheet surface, suitable antioxidants include, for example, hindered phenol compounds and thioether compounds. , Amine compounds and lactone compounds.
Here, the blending amount of the antioxidant is limited to 0.05 to 2.0 parts by weight, but when it is less than 0.05 parts by weight, the oxidation of the resin component mainly composed of EVA is prevented. This effect is small, and the resin component undergoes oxidative degradation during processing to lower the molecular weight, and the melt adheres to the metal roll. On the other hand, if the blending amount is more than 2.0 parts by weight, the antioxidant will plate out on the calender roll during processing, and the appearance of the film or sheet may be impaired, or the surface of the obtained film or sheet may be antioxidant. However, as a bleed-out, printing on a film or sheet, or printing failure or poor adhesive application when an adhesive is applied is caused.
Therefore, in order to prevent oxidation deterioration even during calendering, it can be stably peeled off from the roll, and the antioxidant does not plate out on the calender roll during calendering, so that various problems occur. A compounding quantity is limited to the range of 0.05 weight part-2.0 weight part with respect to 100 weight part of resin components.

Moreover, about the polyolefin resin of melting | fusing point 100 degreeC or more in this invention, the value (Mw / Mn) which remove | divided the weight average molecular weight (Mw) by the number average molecular weight (Mn) is the range of 2.0-4.0. By using materials, it is possible to stably produce films and sheets by calendering, and to produce films and sheets at high speeds when producing thin films that are prone to surface gloss and pattern irregularities or by rotating the calendar roll at high speed. In this case, the surface gloss is good and the pattern is not uneven. In order to improve the surface gloss of a film or sheet obtained by calendar molding and to prevent pattern irregularities, the present invention defines Mw / Mn of EVA as a main component and imparts heat shrink resistance. Even if a polyolefin-based resin is blended, the surface gloss is basically good and pattern unevenness does not occur. However, when the Mw / Mn of the polyolefin resin exceeds 4.0, when the film or sheet is produced by reducing the thickness or rotating the calendar roll at a high speed, the surface gloss is lost and the pattern unevenness occurs. May occur. At that time, when the polyolefin resin is also limited to Mw / Mn of 4.0 or less, the surface gloss is good when a thin film is produced or when a film or sheet is produced at a high speed, Films and sheets with no pattern irregularities can be obtained. On the other hand, when a polyolefin resin having Mw / Mn of less than 2.0 is blended, surface gloss is obtained and pattern unevenness does not occur, but the melt tension of the melt is small like the main component EVA. When the melt is peeled off from the calender roll, sagging due to its own weight occurs, resulting in uneven thickness of the resulting film or sheet. In addition, since the non-Newtonian property of the shear viscosity of the melt is increased, the load applied to the rotating calendar roll is increased, so that a thin film can be produced by narrowing the interval between the calendar rolls, or the calendar roll can be rotated at a high speed. It becomes difficult to produce films and sheets at high speed.
Therefore, in order to produce a uniform film or sheet with surface gloss and no pattern irregularity at high speed by calendar molding under various specification films and a wide range of processing conditions, the polyolefin resin blended with EVA Mw / Mn is preferably in the range of 2.0 to 4.0.
The polyolefin resin having Mw / Mn in the range of 2.0 to 4.0 as described above can be obtained as a commercial product by the progress of polymerization technology using a recent metallocene catalyst. In the present invention, it is preferable to use those commercially available products.

In the EVA resin composition according to the present invention, a conventionally known ultraviolet absorber such as a benzophenone-based, benzoate-based, benzotriazole-based, cyanoacrylate-based, hindered amine-based, or the like, or a low-molecular or high-molecular-weight type, within a range that does not detract from the purpose. Antistatic agents, silica, clay, calcium carbonate, barium sulfate, glass beads, fillers such as talc, flame retardants, antibacterial agents, antifungal agents and the like can be appropriately blended.

Moreover, when producing the base film of this invention, what mixed the resin pellet and the additive simply may be used as a material, and what was melt-kneaded with the kneader previously may be used. Furthermore, the additive is blended with the resin at a high concentration. Usually, a material called a master batch is prepared in advance, and these may be simply mixed, or a resin pellet and a master batch may be melt-kneaded. . As a kneading machine used here, a known apparatus can be used, but a roll that can be easily handled and uniformly dispersed, a single or twin screw extruder, a kneader, a kneader, a planetary mixer, a Banbury mixer, etc. Preferably used.

The composition of the present invention can be applied to a conventionally known calender molding equipment, and has a thickness in the range of 50 to 500 μm. It is flexible, transparent, has a good surface gloss, and has uneven pattern due to flow marks. No film or sheet can be produced at high speed.
The obtained film can be widely used as a tape substrate such as an adhesive tape, a film or sheet for food packaging, agriculture, medical use, industrial material, or stationery. It can be used for food packaging, agriculture, medical, industrial materials, stationery, and the like.

  Next, the present invention will be described in more detail with specific examples, but the present invention is not limited to these examples.

< Reference Example 1>
As EVA, Ultrasene grade 635 (hereinafter referred to as [A1]) manufactured by Tosoh Corporation was used. [A1] has a vinyl acetate content of 25% by weight and an MFR of 2.4 g / 10 min measured at 190 ° C. under a load of 2160 g. The value (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) by the number average molecular weight (Mn) is 2.6. On the other hand, as a polyolefin resin having a melting point of 100 ° C. or higher, a random copolymer polypropylene resin (rPP) obtained by randomly copolymerizing a small amount of ethylene with propylene was used. The rPP used was Sun Allomer, grade PM811M (hereinafter referred to as [B1]) manufactured by Sun Allomer Co., Ltd. This has a melting point of 155 ° C. Here, the mixing ratio of [A1] and [B1] was set to [A1]: [B1] = 80: 20 by weight fraction, and a colorless film having a thickness of 120 μm was produced by a general calendering method. At this time, a fatty acid lubricant (trade name: EXL-5) manufactured by Asahi Denka Kogyo Co., Ltd. was used as a lubricant, and 2.0 parts by weight of this was blended with 100 parts by weight of the resin component. Further, Adeka Stub AO-60 and Adeka Stub 2112 manufactured by Asahi Denka Kogyo Co., Ltd. were used as antioxidants, and each 0.3 parts by weight was blended with 100 parts by weight of the resin.
At the time of calendering, [A1], [B1], EXL-5, AO-60, 2112 were uniformly mixed with a Henschel mixer, and kneaded with a Banbury mixer until the resin temperature reached 168 ° C. to prepare a composition. . This was rolled using an inverted L-shaped four-roll calender molding machine adjusted to 175 ° C., and taken through a cooling process to produce a film having a thickness of 120 μm and a width of 1300 mm. The film was glossy on one side and satin on one side.
And in the film forming process, the peelability of the melted resin from the calender roll, the glossy state on the film surface and the presence or absence of flow marks, the presence or absence of plate out to the calender roll, the flexibility and heat shrink resistance of the film are as follows: The method was evaluated. Moreover, the quality determination regarding each evaluation item was performed in accordance with the following evaluation criteria.
The evaluation results of each example are shown in Table 1. Hereinafter, Examples 1, 2, 4, 5, 7, and 8 in the table are read as reference examples.
[Evaluation criteria]
(1) Evaluation of releasability from calender roll Evaluation of releasability: Good when the sheet-like melt entangled with the calender roll continues to peel from the roll set at 175 ° C. within 2 hours of continuous molding. (○) and not possible (×) when adhered.
(2) Gloss on the surface of the film; the surface state of the obtained film is visually observed, and the case where the gloss is obtained over the entire surface is judged as good (◯). Even if a thin film with a thickness of 80 μm or less is produced with a calender roll rotating at a high speed of 35 m / min or more, the case where the gloss is good is judged as excellent (◎), and passes (good) and excellent (◎). It was. On the other hand, when rough skin with fine grain occurred and the film was cloudy, it was judged as impossible (x).
(3) Presence or absence of a flow mark on the film surface: The surface state of the obtained film was visually observed, and the case where no flow mark was generated over the entire surface was judged as good (◯). If a narrow film with a thickness of 80 μm or less is produced with a calender roll rotating at a high speed of 35 m / min or more, no flow mark is generated. Was passed. On the other hand, when the flow mark had generate | occur | produced on the surface of the film, it was set as impossible (x).
(4) Plate-out to calendar roll: The case where no plate-out occurred on the calendar roll within 2 hours of continuous molding was judged as good (◯), and the case where the plate-out occurred was judged as impossible (×).
(5) Flexibility; Determination on flexibility was carried out using the tensile modulus as an index. Here, the quality was judged by comparing with the tensile elastic modulus of a commonly used soft vinyl chloride film. Among the soft vinyl chloride films, the measurement was performed using the tensile modulus of a film belonging to a low flexibility class (100 parts by weight of vinyl chloride resin and 25 parts by weight of 2-ethylhexyl phthalate as a plasticizer) as a reference value. When the tensile modulus was equal to or less than the reference value, it was judged as good (◯), and when it was larger than the reference value, it was judged as impossible (×).
The tensile elastic modulus was a dumbbell test piece of No. 1, a distance between chucks of 80 mm, a distance between marked lines of 40 mm, a tensile speed of 300 mm / min, and an initial elastic modulus was taken as the tensile elastic modulus.
(6) Heat shrink resistance: Determination of heat shrink resistance was judged by comparing with the heat shrink resistance of a film made of EVA having a vinyl acetate content of 10% by weight. Reference films as EVA, Tosoh Co., Ltd. of Ultrathene, using grade 543, Reference Example 1 and the same type, the same amount of lubricant and antioxidant were blended, using the same equipment as in Reference Example 1 A film having a thickness of 120 μm and a width of 1300 mm was produced under the same processing conditions. Here, when the heat shrinkage resistance is smaller than that of the reference film, the heat shrinkage resistance is good (◯), and when it is larger than that, the heat shrinkage resistance is not acceptable (×). In addition, about the measurement of the heat shrinkage rate of a film, based on JISK6734, it carried out by drawing the 100-mm mark on a 120 mm x 120 mm square film, and reading the length of the mark after heat shrinkage. The heating conditions were a temperature of 100 ° C. and a holding time of 20 minutes, and the heat shrinkage was calculated from the following equation (1).
Heat shrinkage rate = 100 (length after heat shrinkage) / (distance between marked lines before heat shrinkage) (1)

< Reference Example 2>
In Reference Example 2, a film having a thickness of 70 μm was prepared by using the same composition as Reference Example 1 and narrowing the interval between the calendar rolls. By narrowing the roll interval, the flow of the melt in the bank between the calendar rolls was slightly non-uniform, and a partial pattern unevenness accompanying the flow mark reflecting the state occurred slightly on the film surface.

<Example 3>
In Example 3, a composition made of the same material as Reference Examples 1 and 2 except for [B1] was used. Here, rPP (m-rPP) polymerized using a metallocene catalyst was used as the polyolefin resin having a melting point of 100 ° C. or higher. The m-rPP used is a grade (hereinafter referred to as [B2]) manufactured by the company. [B2] has a Mw / Mn of 2.2 measured by GPC and a melting point of 142 ° C. Here, it is the same as Reference Example 2 except that [B1] is changed to [B2]. Although the evaluation result of Example 3 is described in Table 1, since the Mw / Mn of [B2] is 4.0 or less, the flow of the melt in the bank between the calendar rolls is larger than that of Reference Example 2. It was uniform and no flow mark was generated.

< Reference Example 4>
In Reference Example 4, Ultrasene grade 0A54A (hereinafter referred to as [A2]) manufactured by Tosoh Corporation was used as EVA. [A2] has a vinyl acetate content of 15% by weight and an MFR measured at 190 ° C. under a load of 2160 g is 2.0 g / 10 min. Moreover, Mw / Mn measured by GPC is 2.9. On the other hand, high-density polyethylene (HDPE) was used as a polyolefin resin having a melting point of 100 ° C. or higher. The HDPE used is Nipolon Hard, grade 4010 (hereinafter referred to as [B3]) manufactured by Tosoh Corporation. [B3] has a melting point of 136 ° C.
Here, a colorless film having a thickness of 100 μm and a width of 1300 mm was produced at the same processing temperature using the same calendar equipment as in Reference Example 1. At this time, zinc stearate (trade name; Zn-St) manufactured by Nitto Kasei Kogyo Co., Ltd. was used as a lubricant, and 1.5 parts by weight of this was added to 100 parts by weight of the resin. Further, AO-60 and Adeka Stub PEP-36 manufactured by Asahi Denka Kogyo Co., Ltd. were used as the antioxidant, and each 0.5 parts by weight with respect to 100 parts by weight of the resin.

< Reference Example 5>
In Reference Example 5, the same composition as in Reference Example 4 was used, and the distance between the calender rolls was narrowed to produce a film having a thickness of 70 μm. By narrowing the roll interval, the flow of the melt in the bank between the calendar rolls was slightly non-uniform, and a partial pattern unevenness accompanying the flow mark reflecting the state occurred slightly on the film surface.

<Example 6>
In Example 6, a composition made of the same material as Reference Examples 4 and 5 except for [B3] was used. Here, HDPE polymerized using a metallocene catalyst (m-HDPE) was used as the polyolefin resin having a melting point of 100 ° C. or higher. The m-HDPE used was Creolex, grade K4750 (hereinafter referred to as [B4]) manufactured by Asahi Kasei Corporation. [B4] has a Mw / Mn of 3.0 measured by GPC and a melting point of 129 ° C. Here, it is the same as Reference Example 5 except that [B3] is changed to [B4]. Although the evaluation result of Example 6 is described in Table 1, since Mw / Mn of [B4] is 4.0 or less, the flow of the melt in the bank between the calender rolls is larger than that of Reference Example 5. It was uniform and no flow mark was generated.

< Reference Example 7>
In Reference Example 7, Ultrasene grade 628 (hereinafter referred to as [A3]) manufactured by Tosoh Corporation was used as EVA. [A3] has a vinyl acetate content of 20% by weight and an MFR measured at 190 ° C. under a load of 2160 g is 1.3 g / 10 min. Moreover, Mw / Mn measured by GPC is 3.4. On the other hand, linear low density polyethylene (LLDPE) was used as a polyolefin resin having a melting point of 100 ° C. or higher. The LLDPE used was Nipolon-Z, grade ZF260 (hereinafter referred to as [B5]) manufactured by Tosoh Corporation. [B5] has a melting point of 126 ° C.
Here, a colorless film having a thickness of 120 μm and a width of 1300 mm was produced at the same processing temperature using the same calendar equipment as in Reference Example 1. At this time, ethylenebisoleic acid amide (trade name; Alfro AD-281) manufactured by Nippon Oil & Fats Co., Ltd. was used as a lubricant, and 0.75 part by weight of this was blended with respect to 100 parts by weight of the resin. Moreover, the same AO-60 and 2112 as Reference Examples 1 and 2 and Example 3 were used for the antioxidant, and each was blended in an amount of 0.75 part by weight with respect to 100 parts by weight of the resin.

< Reference Example 8>
In Reference Example 8, the same composition as in Reference Example 7 was used, and the interval between the calender rolls was narrowed to produce a film having a thickness of 70 μm. By narrowing the roll interval, the flow of the melt in the bank between the calendar rolls was slightly non-uniform, and a partial pattern unevenness accompanying the flow mark reflecting the state occurred slightly on the film surface.

<Example 9>
In Example 9, a composition made of the same material as Reference Examples 7 and 8 except for [B5] was used. Here, LLDPE (mLLDPE) polymerized using a metallocene catalyst was used as the polyolefin resin having a melting point of 100 ° C. or higher. The mLLDPE used is grade 7P07A (hereinafter referred to as [B6]) manufactured by Tosoh Corporation. [B6] has an Mw / Mn of 2.0 measured by GPC and a melting point of 121 ° C. Here, it is the same as Reference Example 8 except that [B5] is changed to [B6]. Although the evaluation result of Example 9 is described in Table 1, since Mw / Mn of [B6] is 4.0 or less, the flow of the melt in the bank between the calender rolls is smaller than that of Reference Example 8. It was uniform and no flow mark was generated.

<Comparative Example 1>
Comparative Example 1, only [A1] used in Reference Example 1, Reference Example 1 and the same type, and an antioxidant and the same amount of lubricant, with the same calendar equipment as in Reference Example 1, the same processing conditions Thus, a film having the same thickness and width was produced. Although the evaluation result of the comparative example 1 is described in Table 2, the polyolefin resin with melting | fusing point of 100 degreeC or more is not mix | blended, and the heat shrinkage rate of a film is very large.

<Comparative example 2>
In Comparative Example 2, Ultrasene grade 640 (hereinafter referred to as [A4]) manufactured by Tosoh Corporation was used as EVA instead of [A1] in Reference Example 1. [A4] has a vinyl acetate content of 25% by weight, 190 ° C., MFR measured under a load of 2160 g, and 2.8 g / 10 min. Moreover, Mw / Mn measured by GPC is 4.3, and Mw / Mn is out of the claims.
Here, except for using [A4] instead of [A1], a film having the same thickness and width was produced under the same processing conditions using the same calender equipment with the same composition as in Reference Example 1. [A1] and [A4] have almost the same vinyl acetate content and MFR, but Mw / Mn is different, and Mw / Mn of [A4] is out of the claims. Table 2 shows the evaluation results of Comparative Example 2. However, the surface gloss is not obtained, and pattern irregularities due to flow marks also occur.

<Comparative Example 3>
In Comparative Example 3, mLLDPE was used as the polyolefin resin instead of [B1] in Reference Example 1. As the mLLDPE used, grade 7P04B (hereinafter referred to as [B7]) manufactured by Tosoh Corporation was used. [B7] has a melting point of 95 ° C., and the melting point deviates from the claimed range. Here, except for using [B7] instead of [B1], a film having the same thickness and width was prepared under the same processing conditions and the same calendering equipment as in Reference Example 1. Table 2 shows the evaluation results of Comparative Example 3, but the heat shrink resistance does not satisfy the target.

<Comparative example 4>
In Comparative Example 4, Ultrasene grade 510 (hereinafter referred to as [A5]) manufactured by Tosoh Corporation was used as EVA. [A5] has a vinyl acetate content of 6% by weight and a vinyl acetate content outside the claimed range. The MFR measured under a load of 190 ° C. and 2160 g is 2.5 g / 10 min. Moreover, Mw / Mn measured by GPC is 3.4. [B6] used in Example 9 was used as the polyolefin resin having a melting point of 100 ° C. or higher. Here, formulated so that a 50:50 ratio by weight of [A5] and [B6], Reference Example 1 and the same type, by blending the same amount of lubricant and antioxidant, the same calendar equipment as in Reference Example 1 Was used to produce films with the same thickness and width under the same processing conditions. Table 2 shows the evaluation results of Comparative Example 4. Although [B6] has a melting point exceeding 100 ° C., it is somewhat soft among polyolefin resins, and its mixing ratio is 50%. Still, flexibility does not meet the goal.

<Comparative Example 5>
In Comparative Example 5, Ultrasene grade YX23 (hereinafter referred to as [A6]) manufactured by Tosoh Corporation was used as EVA. [A6] has a vinyl acetate content of 42% by weight and a vinyl acetate content outside the claimed range. The MFR measured at 190 ° C. under a load of 2160 g is 0.4 g / 10 min. [B3] used in Reference Example 4 was used as the polyolefin resin having a melting point of 100 ° C. or higher. Here, [A6] and [B3] were blended so as to have a weight ratio of 50:50, the same kind and the same amount of lubricant and antioxidant as in Reference Example 1 were blended, and the temperature was set to 150 ° C. It knead | mixed with this roll. Table 2 shows the evaluation results of Comparative Example 5. The mixing ratio of [B6] is large, the roll temperature is as low as 150 ° C., and EXL-5, which is a lubricant, is also blended in 2.0 parts by weight. Sticked to the roll.

<Comparative Example 6>
Comparative Example 6, the composition used in Reference Example 1, the EXL-5 is a lubricant a composition containing 0.2 parts by weight per 100 parts by weight of the resin, otherwise as in Reference Example 1 An attempt was made to produce a film having the same thickness and width under the same processing conditions using the same calendar equipment. However, the melt adhered to the calender roll, and a film could not be produced.

<Comparative Example 7>
Comparative Example 7, the composition used in Reference Example 1, the EXL-5 is a lubricant a composition containing 4.0 parts by weight per 100 parts by weight of the resin, otherwise as in Reference Example 1 Using the same calendar equipment, films having the same thickness and width were produced under the same processing conditions. Although the film could be manufactured, a plate-out occurred on the calendar roll.

<Comparative Example 8>
The comparative example 8 is a composition which mix | blended 0.02 weight part with respect to 100 weight part of resin with AO-60 and 2112 which are antioxidants with respect to the composition used in the reference example 1, and others. Tried to produce a film with the same thickness and width under the same processing conditions using the same calendar equipment as in Reference Example 1. However, although it peeled off from the calender roll immediately after the start of molding, the melt adhered to the calender roll as the operating time passed.

<Comparative Example 9>
The comparative example 9 is a composition which mix | blended 1.5 weight part with respect to 100 weight part of resin with respect to 100 weight part of resin with respect to the composition used in the reference example 1, AO-60 and 2112 which are antioxidant. Using the same calendar equipment as in Reference Example 1, films having the same thickness and width were produced under the same processing conditions. Although the film could be manufactured, a plate-out occurred on the calendar roll.

According to the calendar-forming ethylene / vinyl acetate copolymer resin composition according to the present invention, the ethylene / vinyl acetate copolymer that is the basis of the composition has specific molecular weight characteristics and vinyl acetate content, and is a polyolefin-based resin. Since the resin also has a specific melting point and molecular weight characteristics, it is flexible, heat-shrink resistant, has a good surface gloss, and has no unevenness due to flow marks. Films that can be manufactured have good thickness accuracy, including alternatives to soft vinyl chloride resin, tape substrates such as adhesive tapes, food packaging, agricultural, medical, industrial It can be used for various purposes as a film or sheet for materials and stationery.

Claims (2)

A value (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn) is in the range of 2.0 to 4.0, and the vinyl acetate content is in the range of 10 to 35% by weight. -Vinyl acetate copolymer 50-95 weight%, melting | fusing point is 100 degreeC or more, and the value (Mw / Mn) which remove | divided the weight average molecular weight (Mw) by the number average molecular weight (Mn) is 2.0-4. 0 der I per 100 parts by weight of the resin component consisting of 5-50% of one or more polyolefin resins excluding the ethylene-vinyl acetate copolymer, a fatty acid number of 21 or more carbon atoms, amide compounds, ethylene A calendar molding ethylene comprising 0.3 to 3.0 parts by weight of a lubricant selected from bisamide compounds, ester compounds and metal soaps, and 0.05 to 2.0 parts by weight of an antioxidant.・ Vinyl acetate copolymer Fat composition. 2. The ethylene / vinyl acetate copolymer resin composition for calendar molding according to claim 1, wherein the ethylene / vinyl acetate copolymer has a melt flow rate (MFR) of 1.3 to 10 g / 10 min. .